Analisis Tingkat Risiko Bencana Tanah Longsor Berbasis Sistem Informasi Geografis di Kecamatan Girsang Sipangan Bolon Kabupaten Simalungun

Abstract

Analysis Of Landslide Risk Levels Based On Geographic Information Systems In The Girsang Sipangan Bolon Subdistrict Of Simalungun Regency

The Girsang Sipangan Bolon sub-district has topographical characteristics that are prone to landslides, triggered by water factors that increase soil weight and activate slip planes. This study aims to identify the level of vulnerability and susceptibility, as well as to analyse and map the risk of landslides in the area. The method used is quantitative with overlay and scoring techniques based on parameters in Permen PU No.22/PRT/M/2007 using a Geographic Information System (GIS). The results of the study mapped the area into five risk classes, namely Very Low covering an area of 4,096 km² (4%), Low covering an area of 35,801 km² (31%), Medium covering an area of 61,474 km² (52%), High covering an area of 13,863 km² (12%), and Very High covering an area of 1,302 km² (1%). Model validation using the ROC curve produced an AUC value of 0.850 (85%), indicating that the model built has a good level of accuracy. The conclusion of this study is that most of the Girsang Sipangan Bolon District is in the moderate landslide risk zone. The resulting risk map can be used as valid input and a basis for relevant parties, such as the Regional Disaster Management Agency (BPBD) and local government, in planning and implementing targeted disaster mitigation measures.